Awkward postures during computer keyboard use have been hypothesized to be one cause of musculoskeletal pain/discomfort as well as musculoskeletal disorders of the upper extremity (MSD-UE). Alternative computer keyboards purport to reduce musculoskeletal pain/discomfort and have been shown to change aspects of keyboard users' kinematics under laboratory conditions. However, research that has examined the effectiveness of alternative keyboards in reducing musculoskeletal pain/discomfort in the workplace is equivocal, and no study has examined the association between changes in kinematics and changes in musculoskeletal pain/discomfort. The Aims of this 3-year prospective double cross-over trial are: 1) to examine the effects of the long-term use of two alternative keyboards on changes in reports of musculoskeletal pain/discomfort and kinematics in comparison to a standard keyboard; 2) to identify which postures and other kinematics variables are associatied with reductions in musculoskeletal pain/discomfort. Seventy-five computer users will be randomly assigned to one of three keyboard use orders: Group 1 - ABC (standard keyboard, fixed angle keyboard, adjustable angle keyboard); Group 2 - BCA (fixed angle keyboard, adjustable angle keyboard, standard keyboard); or Group 3 - CAB (adjustable angle keyboard, standard keyboard, fixed angle keyboard). All subjects will use their assigned keyboards for 4-months before switching to the next keyboard. Every week, subjects will report their musculoskeletal discomfort levels. Just prior to and just after each 4-month intervention subjects' kinematics performances on the keyboards will be recorded in a laboratory setting using 3-dimensional motion capture technology. Relevance: Given the lack of research on alternative keyboards, we cannot determine: 1) whether the implementation of alternative keyboards causes a long term change in keyboarding kinematics; or 2) whether the implementation of alternative keyboards causes a reduction in musculoskeletal pain/discomfort. Without the answers to these questions, we can not adequately judge whether alternative keyboards actual reduce musculoskeletal pain/discomfort or prevent MSD-UE, as is being advertised to the public. The effectiveness of alternative keyboards must be verified to ensure that they are providing interventions that will reduce musculoskeletal pain/discomfort and potentially prevent MSD-UE. [unreadable] [unreadable] [unreadable]